Yes I wasn't convinced once I saw the decals upfront, they looked like an afterthought to me. maybe it's been resprayed at some point in its life, there are some very small 'runs' in the paintwork I noticed which made me wonder. also, for all my looking online I can't find a single other bike that looks this colour..
The seat tube is 27.0
Carlton super course is 26.8 I think...
Bit of a mystery really..
Carlton Super Course of that era is 27.2.
As your bike has had the head badge, it must be a Raleigh, although it was all badge engineering by then anyway!
Mercian King of Mercia Road 1980
Carlton Super Course 1980, Keith Coppell 1981
Colnago Dream 2000, Ribble Audax
GT Zaskar LE